<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>CSS新增选择器</title>
    <style>
        ul{
            width: 300px;
            height: 600px;
            background: pink;
            list-style: none;
        }
        li{
            background: green;
        }
        /* li:first-child{
            background: red;
        }
        li:last-child{
            background: blue;
        }
        li:nth-child(3){
            background: aqua;
        } */
         /* 隔行变色 2n偶数 2n-1奇数 */
         /* li:nth-child(2n){
            background: orange;
         } */
         /* n的倍数变色 */
         /* li:nth-child(3n){
            background: burlywood;
         } */
         /* 第n个以前（+）以后（-）变色 */
         /* li:nth-child(n+3){
            background: fuchsia;
         } */
          input::placeholder{
            color: aqua;
          }
    </style>
</head>
<body>
    <ul>
        <li>1</li>
        <li>2</li>
        <li>3</li>
        <li>4</li>
        <li>5</li>
        <li>6</li>
        <li>7</li>
        <li>8</li>
        <li>9</li>
    </ul>
    <input type="text" placeholder="郑世豪">
</body>
</html>